Troubleshooting a Micrologix 1200

[mtn71]

Probably bit B3:1/5 got "orphaned" (left on) during the power blink.

Exactly. I've moved on to another project now, but when I get the time I plan on sitting down and figuring out why. I really think this program just needs an overhaul. I'll go through and try to label everything soon and post it for you all to check out.

This "Improving this system is the LEAST of his worries right now" always leads to THIS in a small company: "things are on the edge right now." It has always been so. Things never get off the edge because the owner has blinders when it comes to ceratin things: spends money like a drunken sailor on stuff he could do without, but refuses to spend any time or money on stuff that has hurt the business.

I hear what you're saying, but there's a lot more to it than that here. It's just not my place to say anything. I'm currently weighing my options in the event that I need to find work in the near future. I've had a couple job offers recently but nothing that pays enough to pay the bills. I've been through this before, three years ago, with 1400 others when the plant shut down. Back then I got a very good severance and Trade Act benefits (back to school). This time I can't afford to take unemployment very long and may just have to move.

Sorry, don't mean to ramble about that; just stressing a bit lately.

This scheme is nominated for today's Rube Goldberg award!

You've got that right! I thought the exact same thing when I first traced it out. I'm glad to see I called it right even as a beginner.

 

[Clay B.]

Whenever you are ready to tackle this again and clean it up let us know. This really should be a simple system and whoever built it made it entirely to complicated.
This setup is a good example of what I refer to as "exponential confusion". Everyone in here has done it before. You get working on something, like converting some fans from Motor Starters to VFD's, decide to add a PLC to eliminate some relay logic. Things go south and sideways, your out of time so you just create code to fix problems, more problems show up...add more code...more problems...more code...

wa la... you have Rube Goldberg machine. Stay in this field long enough and you will see more of this. I have made a fair amount of coin cleaning up messes like this. I do suggest you get to it sooner than later. If the other code I haven't seen is like what i have seen then this thing is going to be a PITA for a good while.

FYI... Fixing it wont be as bad as you think. First thing I would do instead of trying to figure out what the guy before you did, is figure out what you want the system to do.

Make a flow chart, list of functions, control description..whatever is easy for you to understand and follow...
Then look at what hardware you have... Sounds like you have more than you need to make this system work...
Now comes the fun part... Look at what you have to work with... I will bet several dollars you could simplify this circuit... Once you have a design that will work... install it and see what happens... You can always go back if you first attempt doesn't work...

The key to this kind of work is always leave yourself an exit... As you said it "works" now... so whenever you change something just make sure you can change it back in case you overlooked something... Whenever you make a program change have an original on hand so you can go back to it if your code doesn't work... I will bet that if you look around you will find lots of equipment that can use this kind of attention...

Important rule to rememeber:

"Fixing it" and "making it run" do NOT mean the same thing.

 

[Lancie1]

Sorry, don't mean to ramble about that; just stressing a bit lately.

Stay calm, cool, and collected. You are not going to starve. You will find another job. The economy will improve - next year.

About 5 years ago on this site I said the coming decade is going to be bad and a long hard road to recovery. Many thought I had lost more marbles than usual, but time has proven my prediction. It was an easy prediction: more and more jobs leaving the country due to high corporate federal tax rates, excessive state and local fees, convoluted business regulations, and automated factories needing fewer and fewer workers.

Now that we are through the worst, the jobs remaining and coming back home are going to be high-tech maintenance and operations positions, not assembly-line scut work (that will be done by robots). So plan accordingly.

 

[mtn71]

Thanks everyone. It sounds like you guys really know your stuff. I would like to get the chance to work more on this unit and get it to where it should be. I don't know if that will happen but if it does I will most definitely come to you all for some advice and direction.

Thanks for the good words Lancie. I don't mean to be too negative. Things might work out here. It really is a good place to work. The boss is great; one of those guys that will cut you a ton of slack if you shoot straight with him and give your job 100%, but will make things miserable if you slack off or hide things. I like that.

I would like to focus more on controls as a career direction. My background is spec gasses and chemicals, and machining before that. My last job and this one are in the high tech industry, and it seems like it's not so easy finding other stuff that pays well. Things will work out one way or the other I know; I'm just hoping we don't have to move to find a decent job. My old company has called me several times in the last three years since I left the company, wanting me to come back, but each time was somewhere my wife or I really didn't want to move to. I know, we're picky.

Is there a way to attach the program for you all, other than scanning it into a PDF? I couldn't figure out how, it says "invalid file".

 

[OkiePC]

Is there a way to attach the program for you all, other than scanning it into a PDF? I couldn't figure out how, it says "invalid file".

Yes, right click the file and "Send to compressed (zipped) folder". This will create a zipped file with whatever file(s) selected. Then you can attach the zipped folder.

 

[mtn71]

Thank you! Here it is.